# Sh:846

• Shelah, S. (2008). The spectrum of characters of ultrafilters on \omega. Colloq. Math., 111(2), 213–220.
• Abstract:
We show the consistency of the statement: “the set of regular cardinals which are the characters of ultrafilters on \omega is not convex". We also deal with the set of \pi-characters of ultrafilters on \omega.
• published version (8p)
Bib entry
@article{Sh:846,
author = {Shelah, Saharon},
title = {{The spectrum of characters of ultrafilters on $\omega$}},
journal = {Colloq. Math.},
fjournal = {Colloquium Mathematicum},
volume = {111},
number = {2},
year = {2008},
pages = {213--220},
issn = {0010-1354},
doi = {10.4064/cm111-2-5},
mrclass = {03E17 (03E05 03E35 03E55)},
mrnumber = {2365799},
mrreviewer = {J\"org D. Brendle},
doi = {10.4064/cm111-2-5},
note = {\href{https://arxiv.org/abs/math/0612240}{arXiv: math/0612240}},
arxiv_number = {math/0612240}
}